Lifting magnet

ABSTRACT

A permanent magnet arrangement employing a plurality of individual permanent magnet blocks, the blocks are arranged to provide a suspension or other type lifting magnet with an improved flux distribution pattern.

United States Patent Inventor Bernhard A. Palm 7 Los Angeles, Calif. Appl. No. 17,468 Filed Mar. 9, 1970 Patented Aug. 31, 1971 Assignee Back Mannhcturlng Company Garden Grove, Calif.

LIFTING MAGNET 4 Claims, 4 Drawing Figs.

U,s (I 335/285, 335/304, 294/655, 209/223 lnt. 1101! 7/20 FleldolSeareh 335/285, 291, 304, 306; 209/219, 223 R; 210/222, 223; 294/655 I [56] References Cited UNITED STATES PATENTS 3,454,913 7/1969 lsraelson et al. 335/306 3,489,280 1/1970 lsraelson et al. 209/223 Primary Examiner-Gflarris Attorney-Kenway, Jenney 81. Hildreth ABSTRACT: A permanent magnet arrangement employing a plurality of individual permanent magnet blocks, the blocks are arranged to provide a suspension or other type lifting magnet with an improved flux distribution pattern.

PATENTEU M1931 I92:

SHEET 1 UF 2 FIG.2

ATTOR NEYS FAWN-HD1093! ml 3,602,855

SKELZ 0f 2 s' N s le s FIQ. a

FIGA

INVENM BERNNARD A. PM

ATTORNEYS LIFTING MAGNET DESCRIPTION OF THE INVENTION This invention relates to a suspension or other type lifting magnet employing a plurality of magnetic blocks.

An object of this invention is to provide an improved magnet block arrangement for use in suspension or other type lifting magnets. I v

Another object of this invention is to provide an improved magnet block arrangement in which the magnet blocks are arranged to'improve the efficiency of the lifting magnet.

Another object of this invention is to provide an improved lifting or suspension magnet arrangement employing a plurality of magnet blocks which are disposed with respect to each other to reduce magnetic leakage and to provide a high magnetic field density in the work area.

Still another object of this invention is to provide an improved suspension-type lifting magnet made with a plurality of permanent magnet. blocks which are stacked in the center of the magnet so that the magnet is provided with a central pole face having a relatively large area and at least two outer poles each of which may have lesser areas, the space between the central stack and the outer poles being provided with magnet blocks arranged to reduce magnetic leakage in this space.

3 Other and further objects of this invention will be apparent to those skilled in the art to .which it relates from the following specification, claims and drawing, in which, briefly:

FIG. 1 is a view showing this suspension magnet supported adjacent the outlet end of a conveyor from which magnetic material is to be lifted by the magnet;

FIG. 2 is a sectional view showing the arrangement of the individual magnet blocks in the lifting magnet;

FIG. 3 is a bottom view of the magnet; and

FIG. 4 is a bottom view of a modified magnetic block arrangement in the magnet.

Referring to the drawing in detail reference numeral designates a conveyor which may be used for conveying various products from which magnetic material is to be separated by the magnet 11 that is supported by the linkage 12 adjacent to the outlet end of the conveyor. The linkage 12 supports the magnet 11 so that the bottom 11a of the magnet faces the outlet end of the conveyor. The magnet 11 may of course be used for other applications and the use thereof associated with the conveyor 10 is purely by way ofexample.

The magnet 11 is provided with a plurality of permanent magnet blocks which may be of the ceramic type and the arrangement of these blocks is shown in FIG. 2. The magnet is provided with a mild steel core which includes the top member 13 and end members 14 and 15 which are joined to the top member by welding or the like so that the core is of horseshoe or U-shaped The magnet blocks are stacked between the end members 14 and 15 and these blocks are arranged in three stacks 16, 17 and 18 which may be pressed into the space between the end members 14 and 15 to be held in place by friction or they may be held in place by adhesive such as epoxy cement. The magnet blocks in stack 16 are arranged so that the 73 for example of the outermost one of these blocks is against the end member 14 and this end member thereby becomes the S-pole of the magnet. The innermost one of the magnet blocks 16 which is against the central stack 17 forms the N-pole of the stack 16. Likewise, the outermost block in the stack 18 is positioned so that the S-pole thereofis against the end member 15, for example, and this bled in their unmagnetized condition and after they are assembled in the core they may be magnetized by subjecting them to a-suitable magnetizing force.

The figures arranged below one-half of the magnet in FIG. 2 indicate the magnetic field intensity expressed in gauss at the various distances from the center of the magnet outward and downward from the bottom thereof. Thus at the center of the magnet at a distance of 1 inch from the pole face thereof the magnetic field intensity is 950 gauss, for example, and at a position 3 inches from the center of stack 17 toward the lefthand stack 16 the magnetic field intensity is l 175 gauss at a distance of 1 inch. However, at a distance of 5 inches from the magnet pole faces, the magnetic field intensity at the-center is 260 gauss whereas the magnetic field intensity at the border between stacks 17 and 16 is 215 gauss. Thus, with this magnet arrangement the magnetic field intensity is concentrated toward the center of the work area. All dimensions and gauss numbers used in FIG. 2 are of relative value only'and they are given by way of example only to demonstrate the principle of end member 15 thereby becomes another S-pole of the magthe improved block and core arrangement. Other dimensions and magnetic field strengths may be used if desired within the scope of this invention.

In FIG. 4 there is shown a bottom view of a magnet arrange ment in which the central stack 17 is surrounded by four magnet block stacks l6, 21, 18 and 22. The magnet block stacks 16 and 18 are the same as those shown in FIG. 2 and magnet block stacks 21 and 22 may be the same as stacks l6 and 18 or they may contain a greater or lesser number of magnet blocks, depending upon the intensity of the magnetic field desired on these sides of the central pole 17. The side stacks 21 and 22 are positioned between the side core members 19 and 20, respectively, and the correspondingsides of the central stack 17. The core members 19 and 20 may be made of mild steel and they are joined to the top core member 13 which is provided with suitable extensions to which the side core members 19 and 20 are welded or otherwise attached.

While I have shown and described a preferred form of the invention it will be apparent that the invention is capable of variation and modification from the form shown so that the scope thereofshould be limited only by the scope of the claims appended hereto.

I. In a lifting magnet the combination comprising a core of magnetic material, said core comprising a top member and end members attached to the opposite ends of said top member,'a plurality of block magnets, selected ones of said block magnets forming a stack positioned substantially in the center of said core so that these blocks provide a magnetic central pole on the outer faced the stack of one magnetic polarity and set up a magnetic field in said core such that said end members thereof form end magnetic poles of like polarity which is of opposite magnetic polarity to that of said central pole, additional stacks comprising selected other ones of said magnet blocks being stacked substantially at right angles to said first mentioned stack and being positioned in the space between said first mentioned stack and said end core members to reduce the magnetic leakage through said space.

2. In a lifting magnet as set forth in claim 1 further characterized in that said central pole of said magnet is substantially stronger than either of the additional stacks.

3. In a lifting magnet as set forth in claim 2 further characterized in that said additional stacks are magnetically polarized sothat the magnetic polarities of the ends thereof engaging said end core members correspond to the polarity of the magnetic field set up therein by said central stack.

4. In a lifting magnet as set forth in claim I further characterizedin that said core is provided with side members having magnetic poles of the same polarity as said end members,and additional stacks comprising still other selected ones of said magnet blocks, said last mentioned stacks being positioned in the space between said side members and said central stack for reducing the magnetic leakage in this space.

UNITED STATES PATENT GFFHZE CERTIFICATE OF (IORRECTIQN Patent No. 3,602,855 Dated August 31, 1971 Inventor(s) Bernhard A.- Palm It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 6]. reading "ranged so that the 73 for example of the outermost one of" Should read --ranged so that the S-pole for example of the outermost one of-- and sealed this 23rd day of May 19?2.

(E-SEAL) A L Q6 C2 ROBERT GOTTSCYHALK FIBMAHD N.FBPJTGIYF,JR.

Commissioner' of Patents 4 o ,1 r n note suing O41 leer USCQMM-OC 60375-17 69 QM PC4-1050 (10-59) 

1. In a lifting magnet the combination comprising a core of magnetic material, said core comprising a top member and end members attached to the opposite ends of said top member, a plurality of block magnets, selected ones of said block magnets forming a stack positioned substantially in the center of said core so that these blocks provide a magnetic central pole on the outer face of the stack of one magnetic polarity and set up a magnetic field in said core such that said end members thereof form end magnetic poles of like polarity which is of opposite magnetic polarity to that of said central pole, additional stacks comprising selected other ones of said magnet blocks being stacked substantially at right angles to said first mentioned stack and being positioned in the space between said first mentioned stack and said end core members to reduce the magnetic leakage throUgh said space.
 2. In a lifting magnet as set forth in claim 1 further characterized in that said central pole of said magnet is substantially stronger than either of the additional stacks.
 3. In a lifting magnet as set forth in claim 2 further characterized in that said additional stacks are magnetically polarized so that the magnetic polarities of the ends thereof engaging said end core members correspond to the polarity of the magnetic field set up therein by said central stack.
 4. In a lifting magnet as set forth in claim 1 further characterized in that said core is provided with side members having magnetic poles of the same polarity as said end members, and additional stacks comprising still other selected ones of said magnet blocks, said last mentioned stacks being positioned in the space between said side members and said central stack for reducing the magnetic leakage in this space. 